Doors to rooms typically have a well known latching mechanism to keep the door closed. To open this latching mechanism, it is necessary to turn a door handle. However, often doors to cabinets or closets do not have a latching mechanism. Instead merely pulling on a door handle typically opens these doors. A different type of mechanism is used to prevent these doors from inadvertently opening. The common name for a device that holds a door closed or open is a a “door catch”. There are four common door catch designs. These are: spring-loaded hinges, ball detents, roller catches, and magnetic catches which have a magnet mounted to the doorframe and a piece of metal attached to the door.
It is not commonly recognized that it is very desirable for these door catches to also have some means to absorb energy from a closing door. Without an energy absorbing means, the doors slam against a stop and tend to bounce open unless they were closed carefully. Two magnets exhibiting either magnetic attraction or magnetic repulsion lack this energy absorbing property. Two attracting magnets tend to accelerate a closing door and decelerate an opening door. Two repelling magnets do the opposite. In either case there is no energy absorption mechanism. Non-latching doors with simple magnets would tend to bounce open unless they are closed with a narrow range of energy that can be absorbed by some other means.
Some known door-latching mechanisms include magnetic repulsion to slow a closing door. However, magnetic repulsion is elastic and the energy is returned to a door if there is any bounce.
For example, U.S. Pat. No. 5,782,512 discloses a magnetic field latch assembly for an apparatus having a first element and a second element with the second element having a disengaged position and an engaged position with respect to the first element. The magnetic field latch assembly employs permanent or electromagnets for shock absorption, positioning and latching the first element and the second element. The magnetic field latch assembly includes magnets associated with the first and second elements such that as the first and second elements approach each other, the magnets initially repel each other causing a braking force to slow the relative motion of the first and second elements. When the first and second elements are in the engaged position, the magnets hold the first and second elements in position and minimize vibration and chatter.
U.S. Pat. No. 6,588,811 describes a magnetic door stop/latch which contains a first magnet mounted on or within a door and a second magnet mounted on or within a structure opposing the door, such as a wall, door jamb, door frame or baseboard. When the door is moving towards the opposing structure, the magnetic doorstop may be used to prevent the door from slamming into the opposing structure by virtue of the repulsive forces of the magnets. The magnetic door stop/latch may be switched from repulsive configuration to an attractive configuration that holds the door in position.
The foregoing patents reflect the current state of the art of which the present inventor is aware. Reference to, and discussion of, these patents is intended to aid in discharging Applicant's acknowledged duty of candor in disclosing information that may be relevant to the examination of claims to the present invention. However, it is respectfully submitted that none of the above-indicated patents disclose, teach, suggest, show, or otherwise render obvious, either singly or when considered in combination, the invention described and claimed herein.
The invention described herein absorbs energy and changes the energy into heat. This is a non-contact device that can gently slow a closing door and quietly bring it to a stop at a predetermined point. Furthermore, the invention described herein can be used as a non-contact magnetic brake for other applications. Also, the invention provides a non-contact magnetic coupling device that tends to seek and hold a predetermined relative position of two component parts.